feat(stalk): remove fake genshin stalk

live-probed: /stalk/genshin was NOT real — it just pass-through the raw
SvelteKit __data.json (only nickname/level/nameCardId/profilePicture),
not a full Genshin profile like the Shirokami source (which parses
characters/element/costume/stats via enka-network-api -> get_profile_for_uid).
That proper API is now 404 without an enka token. Removed.

stalk now has 3 real endpoints: github, youtube, twitter.

src/observability/openapi_modules.rs

@@ -74,7 +74,6 @@ use utoipa::OpenApi;
         // ── Stalk module ───────────────────────────────────────────
         crate::presentation::handler::stalk::github_handler,
         crate::presentation::handler::stalk::youtube_handler,
-        crate::presentation::handler::stalk::genshin_handler,
         crate::presentation::handler::stalk::twitter_handler,
         // ── Search module ──────────────────────────────────────────
         crate::presentation::handler::search::bmkg_handler,
@@ -105,7 +104,7 @@ use utoipa::OpenApi;
         (name = "komik", description = "Komik endpoints"),
         (name = "download", description = "Media download endpoints (23 platforms)"),
         (name = "misc", description = "Miscellaneous utilities (currency, gold, server)"),
-        (name = "stalk", description = "User profile stalking (GitHub, YT, Twitter, Genshin)"),
+        (name = "stalk", description = "User profile stalking (GitHub, YT, Twitter)"),
         (name = "search", description = "Search endpoints (BMKG, prayer times, weather, YouTube, Google)"),
         (name = "tool", description = "Utility tools (WHOIS, IP lookup, URL shortener, tracking, hosting)"),
         (name = "image", description = "Image generation (brat static & animated)"),